Chemical Law
by Missmorality
Summary: An AU of Teen Wolf where Stiles and Derek are both the same age in high school: Stiles knew that setting up a prank in Mr Harris's classroom would probably get him in trouble, a suspension from school even, but he had no idea it would send him spiraling into an insane adventure (and romance) involving werewolves and a serial kidnapper. Mostly fluff/ minimal angst.
1. Chapter 1

_A/N Basically this is going to be a funny and (mostly) fluffy Sterek fic that I'm in the middle of writing for one of my best friends as an extremely late Birthday or Christmas present? Originally it was a challenge from her, but I actually am having fun, and I think she forgot about the "challenge" bit. Now I'm rambling. Anyway, I hope you enjoy this, oh buddy oh mine!_

 _Side Note: This is the first fic I've posted on my personal account, because I mostly cowrite stuff with my other friend on another account which you can find by going to my profile._

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 **Chapter 1**

It was the perfect plan for revenge, or so Stiles predicted it would be if Coach hadn't walked in and completely ruined everything. He had spent an hour after school setting up the trip wire outside Jackson's first period classroom. It was connected to a catapult that would deliver sweet, sweet retribution. The wire was taut and Stiles was on the final step of his plan, loading the catapult with a bucket of paint-an alarming shade of chartreuse-when the coach spotted him lurking in the classroom and made a beeline straight for him.

"Stilinski!" Coach yelled, pointing an angry finger in Stiles' direction.

"Coach! Stop!" Stiles frantically waved his hands, but to no avail. "Don't take another—" Too late, the wire was tripped and the paint was catapulted and Stiles was in its trajectory and the Coach, surprised, stopped dead in his tracks. "—step…"

"… What the… is that a catapult…?" Coach struggled to maintain a threatening tone as he spoke between laughs, but eventually was able to complete his duty to reprimand impressively enough with, "get your ass to the principal's office. Now."

Stiles' shoulders slumped, paint dripping down his face and neck, defeated by his own invention.

"Fine," he sighed.

"You know, Stilinski, that color really suits you." Coach commented with a smirk as he pushed Stiles in the direction of the principal.

"Do you really think so?" The yellowy-green teen replied sarcastically as he wiped paint from his eyes. His cheek seared with pain where the lever has smacked him, and he could already feel a large welt forming. Catapults were not meant for short ranged attacks.

Coach took Stiles the short walk to the principal's office, clearly not trusting him enough to get there on his own. The door, plastered with papers advertising school events, fundraisers, and clubs, was not closed all the way and the muffled sound of voices could be heard.

 _Who the hell would be in the principal's office this late after school besides me?_ Stiles wondered as he begrudgingly sauntered over to the waiting-room style chairs and stood next to them, rather than sat in them, he didn't want to leave a stain. Coach guarded the exit and scrolled through his phone, a sort of half-smile, half-scowl on his face.

Ten minutes must have passed, and Stiles still had nothing better to do than listen to muffled voices and watch Coach dumbly look at his phone. Growing agitated, Stiles began absently painting designs on his hands. He made a disgusting-colored smiley face and lost interest almost immediately after. With an exasperated sigh, Stiles let himself fall into the chair, completely forgetting why he had remained standing for so long until it was too late. He sighed again as the still-wet paint made a squish, seeping itself into the fabric, no longer caring about preserving the school's chairs that weren't all that comfortable anyway.

Many more minutes passed before the door finally swung open. Stiles looked up confused, having nearly fallen asleep, and slowly peeled his hand from his cheek. He felt his skin pull with it and release with a subtle snapping sound as a dark-haired boy emerged from the principal's office. Angry green eyes flicked in Stiles' direction for a lingering moment, their expression quickly shifting from confusion to amusement in a split second before looking away, pointedly indifferent. Stiles thought he had seen the hint of a smile, maybe even the start of a laugh, but it disappeared so fast he couldn't be sure. The boy shook his head as he shouldered past coach and made his way down the hallway, Stiles scowled at his back, whoever he was. Stiles thought the boy might be on the basketball team, but he wasn't sure.

He completely dismissed his thoughts when he was herded into the principal's office. Principal Phillips looked up with little enthusiasm as Stiles entered. He didn't even blink at the soaked-in-chartreuse teen.

"Mr. Stilinski…." Phillips sighed, pressing his fingers to his temples. "Why am I not surprised?"

"Do I detect a hint of sarcasm in your voice, Principle Phillips?" Stiles commented cheerily as he shut the door behind him.

"Please, let's just get this over with. It's… been a long day," the older man looked worn down, indeed. His thinning salt and pepper hair was sticking up where it was once meticulously combed down and his glasses were slightly askew. Principal Phillips removed the spectacles from his face and wiped them on a cloth, the lines on his naked face more prominent than ever. Stiles realized it must have been the other boy, the one who'd been in here for so long, that had the principal worn so thin.

"Who was the kid in here before me?" Stiles asked.

"Derek Hale, another headache."

"Why's that?"

"He's failing chemistry, in fact he doesn't even show up for class—wait a second, why am I telling you this? We're supposed to be talking about you."

"I guess we are. So what do you want to know? Let's see… I like long walks on the beach, romantic candle-light dinners, classical novels—"

"Just tell me what why you were installing a catapult filled with yellow paint in Mr. Harris's classroom?"

Stiles explained his plan for revenge against Jackson to Principal Phillips, who was slightly more willing to listen to the story than Coach had been. Phillips nodded almost understandably, being familiar with Jackson he wasn't exactly fond of him either, and when Stiles finished telling his version of the catapult fiasco, Phillips had only one comment to make.

"What if Jackson wasn't the first in the class?"

Stiles stared at him, slowly comprehending the question, certain he'd heard the principal wrong. "What?"

"Well, what if some other student was in the classroom before Jackson and walked into the trip wire, causing the catapult to fire on someone who's innocent."

"Uh…" The truth was, Stiles hadn't actually considered that possibility until now. Phillips shook his head in exasperation. He couldn't believe how absent-minded this straight A student could be sometimes.

"Look, the Coach wants you suspended from the team—" he began.

"No! I mean, please don't suspend me, Principal Phillips, sir…" Stiles clasped his hands together in pleading.

Phillips cleared his throat, continuing where he had been interrupted with, "as I said, I should suspend you, _but…_ "

"Oh, there's a 'but'! Yes, there is a 'but'. Thank you so much."

Phillips stared at him and, taking the hint, Stiles clamped his mouth shut, stowing his hands behind his back to show that he was done interrupting. However, he couldn't stop himself from bouncing slightly on his heels excitedly.

"Since nothing actually happened, I'll give you four weeks of detention, twice a week, and I want you to tutor the boy who was in here before you. Like I said, Derek is struggling in Chemistry, and you're so well versed in that particular subject."

 _Great…_ Stiles thought. He sucked at tutoring because he was too impatient with the student. He just couldn't understand how some people didn't get chemistry like he did. That wasn't really the problem, though. He supposed he could endure through the horrors of tutoring for a few weeks, but the eight detentions were a whole other ordeal because, with his luck, he'd be stuck with…

"You'll serve detention with Mr. Harris on tuesdays and thursdays…"

 _Yep. Of course._ Stiles groaned. That meant he'd miss practice on those days, too, not that anyone other than Scott would notice his absence. The principal filled out a slip and handed it to Stiles. The paper was to be signed by his dad and handed to Mr Harris on tuesday when Stiles reported for his first detention, which was the next day. Stiles huffed a good bye as he stuffed the slip in his backpack then left the principal's office. The coach had also apparently left the vicinity.

The hallways were deserted except for the occasional janitor here and there, but still the emptiness made Stiles shiver. Quickly making his way out of the school, Stiles got all the way to his jeep before he remembered that he was still covered in yellow paint. Grumbling incoherently, Stiles rummaged through the lacrosse bag stowed in the back and found an old tee shirt. It wasn't the freshest smelling shirt in the world, but it would do. Stiles shrugged and slipped the shirt on over his current, paint-covered, one. When his head emerged he noticed a familiar shadowy figure hanging out by the school.

Derek Hale, standing nonchalantly by the "No Skateboarding" sign, was watching him. Stiles couldn't help but think of Derek in the principal's office and how strikingly green his eyes had looked then. He looked like he was waiting for someone, and Stiles momentarily thought about offering him a ride, but to be honest, Derek was a little bit intimidating with that leather jacket, dark hair, and apathetic attitude. Stiles still felt sorry for the other boy, though, realizing how sucky it must feel to be talked to about failing a class, and so, before he could stop himself, Stiles found himself walking towards Derek who was staring right at him with a furrowed brow.

"Hey," Stiles said, when he grew near. He hoped the intense fear he felt wasn't obvious on his face. He tried to smile. Derek didn't respond… he only stared more. Stiles continued awkwardly, "...so I guess I'm going to be tutoring you in chem, er, basically the only weekday I'm free is Wednesdays now, or we could do it on the weekend at your house or mine. But if not, we could go to the public library… or just stick with the school's library on… you know, Wednesdays..."

"Hmmph." Derek's version of a 'yes'? But what was he yessing to? Stiles was quickly running out of things to say to keep the conversation going. If this is what Derek was going to be like during their tutoring sessions, he didn't know if he would be able to survive them.

"Okay, anyway, uh, do you need a ride home, or anything?" Stiles asked weakly.

Derek looked surprised, his eyes flicked from Stiles to his crappy silver jeep parked several yards away.

"Are you waiting for someone?" Stiles said, causing Derek's gaze to snap back to him.

"My sister left without me," Derek admitted, only slightly begrudgingly.

"That sucks. Well, the ride's still open, if you want it." Stiles smiled easier, feeling more at ease now that Derek had finally spoken to him.

Derek looked at the old jeep again, sizing it up, probably considering Stiles's offer, but eventually he shook his head. "No, thanks." He said.

"Okay," Stiles shrugged, turning back toward the parking lot. Derek watched him walk back to his car. He watched as Stiles slightly struggled with the driver's side door and got in, closing it hard behind him.

In his Jeep, Stiles pulled the ancient seat belt across his chest, clicking it into place. The car, which always smelled vaguely of must, started up easier than it normally does. Stiles adjusted his rear-view mirror a little bit, just until he could see Derek standing there, staring straight ahead. Stiles watched Derek through the mirror until he was forced to finally turn, leaving the school, and Derek, behind for the day.

* * *

"Dad? I'm home!" Stiles called as he entered his house. It was late. His dad should be home from work by now. Stiles normally got home after his dad on days when he had lacrosse practice, especially because on those days he would also hang out with his best friend Scott afterwards. But Scott hadn't been in school that day.

"Hey, kid," his dad greeted from the kitchen. "How was school?"

Stiles dropped his backpack by the stairs and made his way through the kitchen, heading straight for the fridge.

"Fine. Scott was absent, though." Stiles said as he stared at their assortment of drinks, trying to decide between root beer or ginger ale. Finally, he grabbed the ginger ale and, closing the fridge door, popped it open, taking a huge swig before turning to his dad, sorting through paperwork at the table.

"That's unusual for him…" his dad commented. He looked up from his papers and Stiles visibly saw him do a double take. Then his jaw dropped cartoonishly. "Stiles?"

"Yes?" Stiles replied, confused by his father's odd behavior.

"Why do you have yellow paint all over your face?" His dad asked.

"Oh, yeah…" Stiles said, as recognition took over. "Wait, one second," he told his dad as he backtracked through the kitchen, found the slip, now crumpled up, in his backpack, and made his way back to his dad. Stiles held out the slip to his father, who already knew what it meant, but still shook his head in disbelief as he read its contents.

" _Eight_ detentions? A paint catapult in Mr Harris's classroom? Stiles, I'm not even going to ask what your plan was." His dad sighed as he signed the slip quickly and handed it back to his son, turning back to all the papers on the table.

"What's that?" Stiles asked, peering over his shoulder. "Work stuff?" If it was, it could be interesting. His dad was the sheriff and this town seemed to attract interesting criminals throughout the years.

"Not for you," his dad said. "Go do your homework, or something."

"Okay, okay," Stiles surrendered to his father's serious expression, and started to head to his room, but not before he got a quick look at the police reports. He only caught a few words of his father's notes in the margins:

 _Missing_

And

 _Full moon?_

That night, Stiles tried calling Scott. There was no answer. A normal person would assume that Scott just didn't feel like answering his phone, that he'd simply been sick that day, but Stiles wasn't exactly a normal person. His anxiety level flared up as he thought of his father's notes and how he looked so exhausted and worn thin when he studied the police reports in front of him. People were missing in Beacon Hills. Apparently, his father thought the moon cycle had some significance, specifically the full moon. The previous weekend had been a full moon, and Scott hadn't been in school on Monday.

 _Scott wasn't in school today._

Had he heard from him at all on Sunday? Stiles wasn't sure. In fact, he couldn't even remember if he'd talked to him on Saturday. No, he was making too many assumptions. He _had_ spoken to Scott on Saturday, they had hung out that day.

Still, he couldn't help worrying. Deciding he should probably just go to sleep, Stiles turned off the light and hopped into bed, but not before making sure his window was locked first as a precaution. Scott would probably be in school the next day… Hopefully.

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 _A/N Thanks for reading the first chapter of Chemical Law_ _! Please review and I hope you look forward to the next chapter! It won't be as long as this one probably, heheh._


	2. Chapter 2

**Chapter 2**

 _A/N: Fair warning, this chapter contains a very bad pun. Read at your own risk. I'm so sorry._

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The morning came, Stiles's alarm startled him awake at 6:30. He groaned groggily, carefully unfolding his body from its awkward sleeping position, then he remembered his worries from last night. Now completely alert, he struggled to find his phone, nearly falling out of the bed, before he snatched it off his dresser. He held it up, unlocking the screen with hopeful fingers, but his face fell when he saw that he had no texts from Scott. Usually he asks for a ride to school by now… Was he going to miss school again?

 _Scott, reply to this if you haven't been kidnapped!_ Stiles texted, then forced himself out of bed.

Stiles put little thought into his outfit that morning, his mind being far too preoccupied. A Tee shirt, jeans, and hoodie was all he needed. His briefs were clean enough to stay unchanged.

After brushing his teeth and splashing his face with cold water, he made his way downstairs to eat some breakfast. It was difficult to finish a bowl of cereal, but he forced himself to gulp down the tasteless flakes, despite the knot of worry slowly getting bigger in his stomach.

On his way to school, he drove by Scott's house, optimistically thinking that he would be standing in his driveway, waiting for a ride to school, and that he'd simply forgotten to text Stilles that morning. Unfortunately, the driveway was empty. Scott's mom's car was there, though, so that was a good sign.

 _Okay,_ Stiles thought, _he's probably still sick._

"He should still call me!" Stiles shouted unintentionally, stepping hard on the gas once he'd passed Scott's house.

By the time he got to school, his level of irritation had subsided. He crookedly parked the Jeep, somehow managing to obtain a spot near the front, and went to grab his lacrosse bag from the back when he remembered that he wasn't going to practice that day, because he had detention with Mr Harris. Suddenly feeling like lacrosse, and detention for that matter, wasn't all that important, he sighed, and let the bag fall out of his hands and onto the floor of this jeep.

Stiles was a ghost throughout his first three classes, barely comprehending anything the teachers were saying, staring dumbly at the whiteboard, unable to even day-dream properly.

During study period, he found himself wandering in and out of bookshelves in the library, scanning the titles without realizing it, until one caught his eye. _Myths and Legends Volume Four: the Lycanthrope._ He stared at it, his brain slowly coming back to life, insane ideas forming in his head once more. Stiles felt revived.

His mind was racing now. Words from his father's reports swam before his eyes. Specifically, two words.

 _Full Moon_.

Grabbing the book and taking a seat at an empty table, Stiles began to read. His eyes scanned the words faster than he thought possibly, only occasionally skipping things that he deemed unnecessary, like the legends of werewolf mating habits. At some point, he began filling up the blank pages of his geometry notebook with notes on werewolves.

Anyone watching would have thought he was just very into his school work. That, or he was cramming for a test at the last minute. Either way, no one questioned it, and Stiles was left alone. Eventually, he looked up from the book, when he was over two thirds of the way through, and noticed that he'd missed gym.

… And lunch.

…. And last period was already half over.

Stiles leaned back in his chair, setting the book down on the table for the first time in hours, apparently. He stared at the clock, wondering if it was correct. Could he really have been so engrossed in his research that he hadn't even heard the bell ring? Thinking about it now, he realized he had just absorbed an immense amount of information, and his head was drowning in it all.

Still, he tried to put it all together and, for the first time, he asked himself why he'd grabbed the book about werewolves. Why he was so obsessed with the whole _full moon_ thing in his father's notes? Did he really believe the disappearances could be something more than just a coincidence? He was starting to think that he did, and more, that it was all caused by a supernatural creature kidnapping people during the full moon, then feeding on them. He wasn't entirely convinced.

As the final bell rang, Stiles got up from his seat a little too quickly, nearly knocking his chair over backwards, and gaining the questioning glances of a few librarians and students. Smiling apologetically, he carefully pushed his chair in, then quickly gathered up all his research materials. He was checking the _Lycanthrope_ book out at the front desk when he remembered that he had to go to detention as well. Briefly, he considered skipping it, but seeing as it was Mr Harris, he didn't really want to risk the potential backlash.

So, after he'd securely stuffed the book into his backpack, being sure to take his time to do so, Stiles found himself begrudgingly dragging his feet toward that familiar chemistry classroom where he'd been caught _chartreuse_ -handed the day before. It took far too short an amount of time to get to the classroom, but figuring it was best to just get the ordeal over with, Stiles went right into the room and was greeted immediately by Mr Harris's contemptuous stare. Even though Stiles was one of Mr Harris's best students, academic-wise, he couldn't really blame the chemistry teacher for hating him so much. Glancing at the faint yellow stain on the floor, Stiles felt that fact bearing more true than ever.

Mr Harris, having had Stiles in his classroom after hours many times before, didn't have to explain the rundown of what he expected for detention. He went back to grading test papers, and Stiles went right to work cleaning the whiteboard, organizing textbooks, wiping graffiti off the desks, and doing any other sick menial task Harris could assign. Luckily, the school had a policy against teachers making students do jumping jacks and pushups, or Stiles was sure Harris would just have him do that for an hour.

After what seemed like eons, the chemistry teacher finally ran out of tasks for his prisoner, but to Stiles's dismay, it had only been about half an hour.

"You can use the rest of this time to do homework, or study," Mr Harris said, seemingly disappointed himself, but for an entirely different reason than his student.

Stiles just stood there, gaping at his teacher, wondering how in the hell that man could have devised a way to slow down time and make his detention last longer. Harris cleared his throat loudly, waking Stiles from his stupor.

He grumbled quietly as he sat down at the front of the room and, while going grab his geometry-turned-werewolf notebook from his bag, a figure caught his eye out in the hallway. A very toned and muscular teen in a dark leather jacket stood in front of the lockers, watching Mr Harris's agape door with piercing green eyes.

 _Is Derek… waiting for me?_ Stiles thought with some doubt, though he had to admit he was a little elated at the idea. Somewhere in the back of his mind, he may have even hoped that were the case, but he was far too preoccupied to notice.

Deciding to ignore Derek for the time being, Stiles tore many pages out of the notebook so he could arrange his notes in front of him, then took the book out of his backpack, opening it to where he'd left off.

Having had time to think to himself while he was doing Mr Harris's chores, Stiles was beginning to see reason more and more. He realized that this whole werewolf theory was most likely impossible, but still he'd found the material interesting.

He'd learned that the first appearance of the wolf-man was near Bedburg, Germany in the late 1500s, and that it was probably just an insane man going around eating people, rather than an actual beast. Sixteen people were torn apart and ravaged, it seemed inconceivable that any human could commit such atrocious murders, so to the villagers of Bedburg it couldn't have been anything but a monster.

Stiles read the rest of the chapter, learning about several more eyewitness account from hundred of years ago, which only served to make him feel even more confident in how ridiculous the idea was. Werewolves were just what this book's title suggested they were; stories. These things were simply impossible. After all, Stiles had seen proof of the laws of science his entire life and a man turning into a giant wolf just didn't follow those laws… At all.

Satisfied with his conclusion, Stiles realized that what he really should do is sneak a look at his father's notes when he got home, and focus on the actual facts of the case. Impatient once more, Stiles glanced at the clock, and took a swift double take when he saw that it was a full ten minutes past the time when he should have been told to leave. He gave Harris an incredulous look, but the chemistry teacher wasn't even paying attention, so, shaking his head in annoyance, Stiles stuffed his notes into the lycan book, making, then grabbed his backpack and, after saying a quick goodbye to Mr Harris, rushed out the door.

Stiles stopped short when he saw Derek Hale, leaning against the lockers somehow looking both bored and annoyed at the same time, and his stomach flipped. So Derek had been waiting for him, but suddenly he got the feeling from the basketball player's expression that he wasn't here to make friends.

"Er, hey, D-derek…" Stiles managed to choke out, giving a feeble smile. Derek rolled his eyes.

"Listen, er, Sticks-"

"Stiles..."

"- I don't have time to be tutored, Okay?"

"I'm not really all that thrilled about it either, but-" Stiles began, the nervousness gone from his voice, only to be replaced by a slight hint of irritation. Before he had finished his thought, however, Derek's attention zipped to the book in Stiles's arms.

"What is that?" Derek demanded, his tone had switched from boredom to aggression in a split second.

"Um…" Stiles glanced at the lycanthropy book with papers sticking out in all directions, and he only grew more annoyed. "This is what's called _a book_. You know, if you actually studied and did your homework you might have encountered one before now."

Derek's eyes turned icy, and Stiles took an involuntary step back.

"Who told you about werewolves?" Derek growled.

"Hold on," Stiles said shakily, holding up his hands in defence. "Are you saying you…?" He trailed off, not sure how to finish the sentence, when he was saved from doing so by the sound of his phone ringing.

He answered immediately, happy for the distraction, only for the feeling to be ripped away at the sound of his father's voice. He listened quietly as the chief of police gave his news both matter-of-factly and with an air of sadness.

Derek stood by watching, uncharacteristically polite. He made it a point not to eavesdrop, but couldn't help but notice the major difference in the other boy's behavior.

Stiles's blood ran colder and colder as his father finished with the words, "I'm sorry, son..." After hanging up almost before his father had finished the sentence, he stood there for a moment, staring at his cellphone.

What?" Derek snapped, with only slightly less hostility than before.

Stiles's looked at him, at a loss for words. Both Scott and Mrs McCoy had been officially labeled as missing.

* * *

 _A/N: Thank you to those who favorited and/or followed this story! That fact actually motivated me to finish up chapter 2 sooner. On that note, sorry, if this chapter seems short to you or like it's just filler, but the rest of the story is pretty much all set up now, and the next chapter will probably be longer with more action and Sterek moments!_

 _Anyway, please review if you want. I'm always up for some constructive criticism :D_


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